summaryrefslogtreecommitdiffstats
path: root/lib/blkid/devno.c
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--lib/blkid/devno.c242
1 files changed, 242 insertions, 0 deletions
diff --git a/lib/blkid/devno.c b/lib/blkid/devno.c
new file mode 100644
index 0000000..b1cadc9
--- /dev/null
+++ b/lib/blkid/devno.c
@@ -0,0 +1,242 @@
+/*
+ * devno.c - find a particular device by its device number (major/minor)
+ *
+ * Copyright (C) 2000, 2001, 2003 Theodore Ts'o
+ * Copyright (C) 2001 Andreas Dilger
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ * %End-Header%
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+#if HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+#include <stdlib.h>
+#include <string.h>
+#if HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#if HAVE_SYS_STAT_H
+#include <sys/stat.h>
+#endif
+#include <dirent.h>
+#if HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#if HAVE_SYS_MKDEV_H
+#include <sys/mkdev.h>
+#endif
+#ifdef HAVE_SYS_SYSMACROS_H
+#include <sys/sysmacros.h>
+#endif
+
+#include "blkidP.h"
+
+#if defined(__GNUC__) && __GNUC__ >= 8
+/* gcc incorrectly thinks the destination string is not being null-terminated */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wstringop-truncation"
+#endif
+
+char *blkid_strndup(const char *s, int length)
+{
+ char *ret;
+
+ if (!s)
+ return NULL;
+
+ if (!length)
+ length = strlen(s);
+
+ ret = malloc(length + 1);
+ if (ret) {
+ strncpy(ret, s, length);
+ ret[length] = '\0';
+ }
+ return ret;
+}
+
+#if defined(__GNUC__) && __GNUC__ >= 8
+#pragma GCC diagnostic pop
+#endif
+
+char *blkid_strdup(const char *s)
+{
+ return blkid_strndup(s, 0);
+}
+
+/*
+ * This function adds an entry to the directory list
+ */
+static void add_to_dirlist(const char *name, struct dir_list **list)
+{
+ struct dir_list *dp;
+
+ dp = malloc(sizeof(struct dir_list));
+ if (!dp)
+ return;
+ dp->name = blkid_strdup(name);
+ if (!dp->name) {
+ free(dp);
+ return;
+ }
+ dp->next = *list;
+ *list = dp;
+}
+
+/*
+ * This function frees a directory list
+ */
+static void free_dirlist(struct dir_list **list)
+{
+ struct dir_list *dp, *next;
+
+ for (dp = *list; dp; dp = next) {
+ next = dp->next;
+ free(dp->name);
+ free(dp);
+ }
+ *list = NULL;
+}
+
+void blkid__scan_dir(const char *dirname, dev_t devno, struct dir_list **list,
+ char **devname)
+{
+ DIR *dir;
+ struct dirent *dp;
+ char path[1024];
+ int dirlen;
+ struct stat st;
+
+ if ((dir = opendir(dirname)) == NULL)
+ return;
+ dirlen = strlen(dirname) + 2;
+ while ((dp = readdir(dir)) != 0) {
+ if (dirlen + strlen(dp->d_name) >= sizeof(path))
+ continue;
+
+ if (dp->d_name[0] == '.' &&
+ ((dp->d_name[1] == 0) ||
+ ((dp->d_name[1] == '.') && (dp->d_name[2] == 0))))
+ continue;
+
+ sprintf(path, "%s/%s", dirname, dp->d_name);
+ if (stat(path, &st) < 0)
+ continue;
+
+ if (blkidP_is_disk_device(st.st_mode) && st.st_rdev == devno) {
+ *devname = blkid_strdup(path);
+ DBG(DEBUG_DEVNO,
+ printf("found 0x%llx at %s (%p)\n", (long long)devno,
+ path, *devname));
+ break;
+ }
+ if (list && S_ISDIR(st.st_mode) && !lstat(path, &st) &&
+ S_ISDIR(st.st_mode))
+ add_to_dirlist(path, list);
+ }
+ closedir(dir);
+ return;
+}
+
+/* Directories where we will try to search for device numbers */
+static const char *devdirs[] = { "/devices", "/devfs", "/dev", NULL };
+
+/*
+ * This function finds the pathname to a block device with a given
+ * device number. It returns a pointer to allocated memory to the
+ * pathname on success, and NULL on failure.
+ */
+char *blkid_devno_to_devname(dev_t devno)
+{
+ struct dir_list *list = NULL, *new_list = NULL;
+ char *devname = NULL;
+ const char **dir;
+
+ /*
+ * Add the starting directories to search in reverse order of
+ * importance, since we are using a stack...
+ */
+ for (dir = devdirs; *dir; dir++)
+ add_to_dirlist(*dir, &list);
+
+ while (list) {
+ struct dir_list *current = list;
+
+ list = list->next;
+ DBG(DEBUG_DEVNO, printf("directory %s\n", current->name));
+ blkid__scan_dir(current->name, devno, &new_list, &devname);
+ free(current->name);
+ free(current);
+ if (devname)
+ break;
+ /*
+ * If we're done checking at this level, descend to
+ * the next level of subdirectories. (breadth-first)
+ */
+ if (list == NULL) {
+ list = new_list;
+ new_list = NULL;
+ }
+ }
+ free_dirlist(&list);
+ free_dirlist(&new_list);
+
+ if (!devname) {
+ DBG(DEBUG_DEVNO,
+ printf("blkid: couldn't find devno 0x%04lx\n",
+ (unsigned long) devno));
+ } else {
+ DBG(DEBUG_DEVNO,
+ printf("found devno 0x%04llx as %s\n", (long long)devno, devname));
+ }
+
+
+ return devname;
+}
+
+#ifdef TEST_PROGRAM
+int main(int argc, char** argv)
+{
+ char *devname, *tmp;
+ int major, minor;
+ dev_t devno;
+ const char *errmsg = "Couldn't parse %s: %s\n";
+
+ blkid_debug_mask = DEBUG_ALL;
+ if ((argc != 2) && (argc != 3)) {
+ fprintf(stderr, "Usage:\t%s device_number\n\t%s major minor\n"
+ "Resolve a device number to a device name\n",
+ argv[0], argv[0]);
+ exit(1);
+ }
+ if (argc == 2) {
+ devno = strtoul(argv[1], &tmp, 0);
+ if (*tmp) {
+ fprintf(stderr, errmsg, "device number", argv[1]);
+ exit(1);
+ }
+ } else {
+ major = strtoul(argv[1], &tmp, 0);
+ if (*tmp) {
+ fprintf(stderr, errmsg, "major number", argv[1]);
+ exit(1);
+ }
+ minor = strtoul(argv[2], &tmp, 0);
+ if (*tmp) {
+ fprintf(stderr, errmsg, "minor number", argv[2]);
+ exit(1);
+ }
+ devno = makedev(major, minor);
+ }
+ printf("Looking for device 0x%04llx\n", (long long)devno);
+ devname = blkid_devno_to_devname(devno);
+ free(devname);
+ return 0;
+}
+#endif